Posts Tagged ‘Theoretical Physics’

… physicists ruin physics
(bumper sticker — I doubt if it exists, but it should)

The efficacy of a computer simulation (or of any other numerical computation) in predicting the behaviour of a physical system, crucially hinges on two ingredients:
1) The reliability of the underlying mathematical model adopted to describe the physical system of interest.
2) The accuracy of the numerical technique utilized.
This is just as true for physics as it is for any other field of inquiry — biology, economics, sociology, engineering, in fact for any research endeavour that relies on complex mathematical models, too intricate to be studied analytically.

given that every other day we seem to be telling each other appalling stories of disgraceful article refereeing to which we are subjected, I think we should all try and agree, first of all among ourselves, on what constitutes “bad refereeing”, and pledge to each other not to do it. Ever.
After all, it is as good a starting point as any other. If we are successful at convincing others to agree to our code of conduct, we might see some difference in the future.

What is the job of a theoretical physicist ? Isn’t physics an experimental science ? Should discoveries not always occur as a result of reproducible, controlled laboratory observations ? Perhaps in no other scientific discipline is the division between “theorists” and “experimentalists” so well-defined and rigid as in physics.

In one of his latest posts, Doug Natelson describes the difference between first-principle calculations, and those which instead are based on so-called “toy models”.
First-principle calculations are aimed at incorporating as much as possible of reality as it is known, down to the most fundamental constituents and interactions as required (for example, in Condensed matter physics that reasonably amounts to regarding, e.g., a crystalline solid, as an assembly of electrons and ions, all interacting electrostatically).
But theoretical physicists like to play with “toy models” as well, i.e., highly idealized representations of the physical reality, that cannot (and are not even designed to) provide a quantitatively accurate description of a particular physical system, but rather attempt to capture only its bare essentials.
What is the point of such an exercise ?

Much of the current research work in theoretical physics involves numerical computation. This is because calculations themselves are too complicated to be tackled analytically (i.e., with pencil and paper). The writing of a code suitable to carry out calculations of a specific type, especially one that is flexible, easy enough to use and relatively general in scope, is a major undertaking, one that can consume the better part of a doctoral thesis, for example.
Once the code is functioning, and the project for which it was initially written has been completed, the researcher who developed it often finds him/herself in the somewhat enviable position of having a tool that may be of interest to others, with which different, relevant and important problems may be investigated.
One issue that often comes up in conversation is: what is the accepted protocol for sharing a code with other investigators, or groups ?